What happened

Shares of Moderna (MRNA -3.36%) were jumping 5.7% higher at 11:17 a.m. EDT on Friday. One potential reason behind the gain is that investors expect that Moderna will benefit from issues that AstraZeneca (AZN -1.12%) and Johnson & Johnson (JNJ -0.21%) are experiencing with their COVID-19 vaccines.

On Wednesday, the European Medicines Agency (EMA) reported a possible link between AstraZeneca's COVID-19 vaccine and unusual blood clots. United Kingdom authorities issued a recommendation that people under age 30 receive another vaccine if possible.

Meanwhile, the U.S. Centers for Disease Prevention and Control (CDC) expects the allocation of Johnson & Johnson's COVID-19 vaccine to plunge by 85% next week. This drastic reduction stems from manufacturing problems found in a facility operated by Emergent BioSolutions, a contract manufacturer J&J engaged to help produce its vaccine.

Two COVID-19 vaccine vials upright and two vials toppled over

Image source: Getty Images.

So what

It's unlikely that Johnson & Johnson's problems will boost Moderna's fortunes in the immediate future. The U.S. government already has supply deals in place to obtain 300 million doses of Moderna's COVID-19 vaccine plus another 300 million doses of the vaccine developed by Pfizer and BioNTech. That's enough to fully vaccinate all Americans in the age groups for which COVID-19 vaccines are currently authorized even without J&J's vaccine.

Johnson & Johnson has stepped in to help resolve the manufacturing issues with the production of its COVID-19 vaccine. The company still expects to deliver nearly 100 million doses of its vaccine by the end of May. 

AstraZeneca's woes, however, could potentially help Moderna. It's possible that some governments could choose to go with rival COVID-19 vaccines for future supply agreements because of the safety concern identified by the EMA. It should be noted, though, that the reported blood clots are a very rare side effect. The EMA maintains that the benefits of AstraZeneca's vaccine outweigh the risks.

Now what

Moderna's chief medical officer, Tal Zaks, made an announcement on Wednesday that could be more important to the biotech stock than the AstraZeneca or Johnson & Johnson stories. Zaks said that Moderna expects its booster shot targeting coronavirus variants should be available by the end of 2021. The emergence of these variants could mean that Moderna will be able to count on strong recurring revenue from its COVID-19 vaccine after the pandemic ends.